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Occurrence of Rhodamine B (RhB) contamination in paprika caused by agricultural materials during the vegetation process has been reported. It may transfer during the process of active compounds extraction, and eventually exist in final products. Herein, the re-distribution of RhB during the extraction process was assessed in terms of RhB contents, as well as mass, color value and capsaicinoids yield of each process. Results revealed that natural RhB contamination at 0.55-1.11µg/kg originated from raw paprika fruit then transferred with the extraction proceeded. About 95.5% of RhB was found in red oleoresin. After separation of red oleoresin, 91.6% of RhB was remained in capsicum oleoresin, only 3.7% in paprika red. These results were consistent with total capsaicinoids recovery of each product. The RhB levels in edible capsicum oleoresin in our present study at 0.01-0.34µg/kg did not exceed the legal limits established by the European Union.

Tomato peel is a promising source of lycopene. Benzo(a)pyrene, benzo(a)anthracene, benzo(b)fluoranthene, and chrysene (PAH 4) are polycyclic aromatic hydrocarbons (PAHs) classed as priority pollutants by the European Union that can be sorbed by tomato peel and transferred to lycopene products. Here, the transfer of PAH 4 to extracted lycopene was assessed. Between 77.69% and 102.99% of PAH 4 in tomato peel was transferred to tomato oleoresin. The PAH transfer rate was closely related to the log (octanol-water partition coefficient). PAH partitioning depended on the PAH solubility in the different phases used. Only 0.028%-0.058% of the PAHs entered lycopene crystals, the rest remaining in the residue. This indicated that crystallization efficiently excluded PAH 4. Lycopene crystals 96.71% pure were produced that could be used in various commercial products. An exposure and risk assessment indicated that PAH 4 in lycopene do not pose strong risks to people consuming lycopene microcapsules.

This paper reports on the environmental rhodamine B (RhB) contamination in capsicum caused by agricultural materials during the vegetation process. Ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was applied to detect 64 capsicum samples from China, Peru, India and Burma. Results demonstrated that RhB was found in all samples at low concentrations (0.11-0.98 μg/kg), indicating RhB contamination in capsicums is probably a ubiquitous phenomenon. In addition, studies into soils, roots, stems and leaves in Handan of Hebei province, China showed that the whole ecologic chain had been contaminated with RhB with the highest levels in leaves. The investigation into the agricultural environment in Handan of Hebei province and Korla of Xinjiang province, China demonstrated that the appearances of RhB contamination in the tested capsicums are mainly due to the agricultural materials contamination. The study verified that environmental contamination should be an important origin for the RhB contamination in capsicum fruits.

Current research has demonstrated the presence of sub parts per billion levels of Sudan dye in paprika fruits during the vegetation process, which is difficult to understand on the basis of the conventional concept of cross-contamination or malicious addition. Detailed surveys on Sudan dyes I-IV in paprika fruits, soils, and agronomic materials used from seven fields of Xinjiang (China) were conducted to investigate the natural contamination. Results revealed that Sudan dyes II-IV were never detected and that Sudan I existed in almost all samples except for the mulching film and irrigation water. The higher total amount of Sudan I in soils, pesticides, and fertilizers compared to coated seeds indicated the combination of Sudan I-contaminated soils and application of Sudan I-containing agronomic materials constitutes a major source of 0.18-2.52 μg/kg levels of Sudan I in fruits during the growth period. The study offers a more reasonable explanation for the previously observed Sudan I in paprika fruits.

A new design concept of electrochemical pH-controllable molecular switch is presented by utilizing a new electrochemical measurement system as switching transducer. A pH sensor is connected in series between the terminal points of the working and counters electrodes of a potentisostat, and immersed in the solution together with a reference electrode, establishing a novel electrochemical measurement system. In this system, the variation of pH-controllable interface potential at the pH-sensing film/solution interface can be converted to current response when amperometry technique is employed. Based on this unique current–potential relationship, a pH-controllable switch is designed to monitor the protonation and deprotonation reaction of pH-sensing molecule. The current direction interchanges between positive and negative via pH control, illustrating a reversible conformation transition between protonated state and deprotionated state of molecule. The magnitude of current value represents the degree of protonation and deprotonation reaction of molecule. The strategy is successfully demonstrated with a remarkably reversible polyaniline-based pH-controllable switch, which confirms the feasibility of the novel electrochemical measurement system as switching transducer for designing electrochemical pH-controllable switches. This study may open up a potential avenue to construct the electrochemical pH-controllable switches.

Experiments were conducted to assess the role of colonization of alfalfa roots by an arbuscular mycorrhizal (AM) fungus (Glomus etunicatum) in conjunction with a non-ionic surfactant (Triton X-100) in dissipation of phenanthrene in a soil spiked with phenanthrene at 0, 2.5, 5.0 and 10.0 mg kg(-1). After plant harvest the residual phenanthrene concentration in the soil decreased markedly. Mycorrhizal treatment enhanced phenanthrene dissipation in the rhizosphere and bulk soils irrespective of phenanthrene application rate. Addition of Triton X-100 resulted in the highest phenanthrene concentration in the rhizosphere soil among the treatments, while the lowest phenanthrene concentration in the bulk soil was obtained by AM inoculation and amendment with Triton X-100. AM inoculation and addition of the surfactant consistently promoted phenanthrene dissipation in the soil and decreased the microbial biomass based on phospholipid fatty acid (PLFA) analysis. PLFA profiles demonstrated that AM inoculation together with addition of Triton X-100 altered the microbial community structure in the rhizosphere soil. The results of this study provide a reference value for phytoremediation of soil contaminated by organic pollutants. (c) 2008 Elsevier B.V. All rights reserved.

The voltammetric behavior of trepibutone at a pencil graphite electrode (PGE) is investigated by cyclic and square-wave voltammetry in B–R buffers (pH 1.81–11). Two pairs of well-defined reversible peaks are observed at 1.06 and 1.24 V over the pH range of 1.81–6.80, which are attributed to the one-electron transfers without proton in two different chemical forms of trepibutone, protonated and non-protonated. The cathodic peaks correspond to a one-electron reduction of the carbonyl of the benzoyl group, and the anodic peaks correspond to a one-electron oxidation of its free radical. In addition, when the trepibutone concentration is higher, another reversible peak at 0.39–0.26 V is observed in the pH range of 1.81–3.00, corresponding to the transfer of two electrons and two protons, which may be due to the dimer of the trepibutone free radical. Based on the oxidation peak at 1.06 V in B–R buffer (pH 1.81), a square-wave voltammetric method is proposed for the determination of trepibutone. A linear relationship is obtained from 0.24 to 10 μg mL −1 with a detection limit of 20 ng mL −1 . The PGE exhibits the best reproducibility and highest sensitivity without any additional procedure for the renewal of the electrode surface. The proposed method is applied to the determination of trepibutone in pharmaceutical formulations.

Sudan dyes in spices are often assumed to arise from cross-contamination or malicious addition. Here, experiments were carried out to identify the potential source of Sudan I-IV in Capsicum fruits through investigation of their contents in native Capsicum tissues, soils and associated agronomic materials. Sudan II-IV was not detected in any of the tested samples. Sudan I was found in almost all samples except for the mulching film. Sudan I concentrations decreased from stems to leaves and then to fruits or roots. Sudan I levels in soils were significantly elevated by vegetation treatment. These results exclude the possibility of soil as the main source for Sudan I contamination in Capsicum fruits. Further study found out pesticide and fertilizer constitutes the major source of Sudan I contamination. This work represents a preliminary step for a detailed Sudan I assessment to support Capsicum management and protection in the studied region.

A greenhouse pot experiment was carried out to investigate the effect of the arbuscular mycorrhizal fungus Glomus etunicatum on the uptake of atrazine (ATR) and cadmium (Cd) from soil by maize (Zea mays L.). Mycorrhizal colonization led to an increase in the accumulation of Cd and ATR in maize roots but a decrease in the shoots. Atrazine alleviated the adverse effects of Cd on maize growth, and this was more pronounced in the inoculated plants. An increase in Cd accumulation by maize roots was observed when ATR was also present. After harvest, the residual ATR concentration in the soil decreased markedly. With mycorrhizal inoculation the amount of residual ATR decreased more in the bulk soil but less in the rhizosphere soil compared to the noninoculated controls. Cadmium application significantly decreased the ATR residual concentrations in both the rhizosphere and bulk soils irrespective of inoculation treatment.